Coetzee was born in Phokwane Local Municipality. His father was a postal worker and himself worked for the postal service before becoming an investigator in 1969. Starting out as a constable in 1972 he rose through the ranks, and advanced his cause on secondment with the Rhodesian armed forces. He was promoted to captain in the security police and in 1980 became the first commander of the secret police base on the Vlakplaas farm near Pretoria. In 1981, he was "assigned" the murder of Griffiths Mxenge.[4]

His role as Vlakplaas commander ended after 18 months, following a disaster when two of his operatives were arrested on a sortie in Swaziland. He worked shortly in narcotics and the flying squad during which time an internal disciplinary inquiry found him guilty of insubordination, obscene phone calls and distribution of a pornographic video. In 1986, he was found medically unfit to serve because of diabetes, and was discharged on a meagre pension. After exposing the existence of the unit in 1989[5] he went on the run, staying in 38 houses in four countries – including a spell in London, where he joined the ANC and expressed his support for Nelson Mandela.

He was minded by the current president Jacob Zuma. He returned to South Africa in 1993. He was among the first to apply for amnesty with the Truth and Reconciliation Commission when it was created and was granted amnesty on 4 August 1997.[6]

He fell out of grace with the ANC and was employed by EduSolutions, which supplied textbooks on behalf of the government to Limpopo province. In July 2012, he told the media about huge piles of undelivered textbooks.[citation needed]

Eugene de Kock, a former commander of Vlakplaas, was convicted in 1997 of attempting to murder Coetzee.[7]